LOS ALAMITOS, Calif. (AP) — Interstate 405 in Southern California was closed for several hours early Wednesday after three steel beams weighing 50,000 pounds each tumbled from a construction site, injuring a construction worker who also fell onto the lanes below, transportation officials said.

The accident happened around 2:45 a.m. as crews were setting the 130-foot beams onto a new overpass in the Rossmoor area just east of Long Beach, said David Richardson with the California Department of Transportation. One beam on a crane bumped two already in place, and all three crashed down into the southbound lanes of I-405.

One worker fell from the overpass onto the pavement below, Richardson said. He was transported to a hospital with unknown injuries.

A second worker was left dangling but managed to climb back up and was not hurt.

"He was pretty shaken up," Richardson said.

All lanes at the busy Interstate 605 interchange were closed during the morning commute as workers used a crane to remove the beams, Caltrans said. The northbound side was reopened shortly before 7 a.m. and southbound lanes were reopened about 30 minutes later.

During the shutdown, traffic on the key north-south artery was backed up for several miles in both directions.